DE 101 36 438 A1 discloses a sensor arrangement in an antifriction bearing with which physical quantities acting on the bearing can be determined. In the case of this sensor arrangement, the forces and moments acting on bearing shells of the antifriction bearing are recorded in such a way that the mechanical stresses or other physical influences on the bearing shells are detected by sensor elements arranged on the bearing shells and electronic parts optionally combined with them. The sensors are in this case formed as strain gages, which are preferably fastened in a peripheral groove of a fixed bearing shell. It is possible for the shell to be both the inner bearing shell or the outer bearing shell of an antifriction bearing.
According to this publication, the sensor arrangement may be arranged on a substrate acting as a carrier material. Moreover, the resistive strain gages of the sensors described above are applied over an insulating layer on an inflexible metal intermediate carrier, such as for instance a small plate. According to this publication, the carrier material, formed as a leadframe, may be welded onto or pressed into the antifriction bearing at a suitable location.
In addition, it is known from this DE 101 36 438 A1 that both axially measuring and tangentially measuring resistive strain gages in full-bridge or half-bridge connection can be applied to the metal intermediate carrier. Moreover, these known bridge circuits may also be connected to electronic devices with which signal evaluation and signal transmission to further measuring points or other evaluation circuits or to a connection plug is possible.
The signal transmission in the case of this known measuring bearing may take place serially via a digital bus or an analog bus. Accordingly, this mechatronic arrangement allows the additional direct assignment of devices for electronic signal processing to the antifriction bearing, so that for example digital output signals can be generated and the sensor arrangement can be connected directly to a bus system, for instance in a motor vehicle.
Furthermore, DE 42 18 949 A discloses a force measuring bearing in which the sensors take the form of force measuring films and are inserted in a peripheral groove of a bearing part. These film sensors comprise two laminated-together layers of polymer, one layer being coated with electrodes engaging in one another in a comb-like manner and a resistance material being applied to the other layer. If a force is applied to the sensor, the resistance material closes the electrodes more or less in parallel, so that the electrical resistance decreases with increasing pressure loading. This pressure-dependent change in resistance can then be precisely determined with the aid of evaluation electronics.
Furthermore, DE 103 04 592.9, which is not a prior publication, discloses an antifriction bearing of the generic type with a measurement data recording and/or measurement data processing system which comprises sensors, strip conductors and microcomputers which are arranged on at least one common flexible carrier film and are fastened on a part of the bearing.
In the case of this antifriction bearing, the sensors and electronic devices together with their flexible carrier film are fastened for example on the fixed outer bearing race, and preferably fastened there in an annular groove on the outer side of the bearing race.
With regard to the sensors, which in this measurement data recording and measurement data processing system are integrated on the flexible carrier film, it is provided that they are formed at least for recording the rotational speed and/or the direction of rotation of a body mounted in the bearing, the radial and/or axial force acting on the bearing, the direction of the force, the noise of the bearing, the temperature of the bearing and any unbalance that may occur.
According to this prior art, the electronic devices may be built up as individual discrete electronic devices or else as complex and very small microcomputers, which are connected to the sensors and also to one another via signal transmission lines on the flexible carrier film. The sensors, the sensor lines and/or data lines and the electronic devices are applied to the flexible carrier film for example by means of a thin-film method (PVD method) or by means of a sputtering technique and are covered with an elastic and electrically nonconducting covering material.
Finally, it is known from DE 42 31 610 A1 and the publications US 2003/59975 A1, US 2003/59984 A1, US 2003/59987 A1 and US 2003/60038 A1 to use an organic material for the production of electronic structures and to apply this to a carrier substrate for example by means of liquid-jet printing (ink-jet printing).